The present disclosure relates to a fixing device, and to an image forming apparatus incorporating a fixing device. More particularly, the present disclosure relates to a fixing device including a blowing member for blowing air, and to an image forming apparatus incorporating such a fixing device.
In image forming apparatuses, for the purpose of fixing a toner image to a sheet (recording medium), there are widely used fixing devices that include a fixing member composed of a heating roller (heating rotary member) and a pressing roller (pressing rotary member) held in pressed contact. In such a fixing device, the sheet is passed through a fixing nip formed between the heating and pressing rollers so that the toner image is subjected to heat and pressure; the toner image is thus fused and fixed to the sheet.
However, when small sheets are handled for fixing, whereas a sheet-passage region on the surface of the fixing member where a sheet passes loses heat to the sheet and becomes cold, a non-sheet-passage region where the sheet does not pass remains hot. In particular, when sheets are passed continuously, keeping the sheet-passage region on the fixing member at a fixing temperature may cause the non-sheet-passage region on the fixing member to overheat. Inconveniently, the fixing member and other components may then be exposed to temperature higher than their heatproof temperature and thermally break down.
As a solution, there are known fixing devices that include a blowing member which blows air toward opposite end parts of a fixing roller (heating roller). With such a fixing device, even when small sheets are passed continuously, the non-sheet-passage region (opposite end parts of the fixing roller) is prevented from overheating by the air that is blown to the opposite end parts of the fixing roller.